Answer:
Ibn Sina
Explanation:
Ibn Sina was an Islamic philosopher and scientist. There were many fields of research on which he worked but his services to the field of medicine are remarkable. Ibn Sina learned that patients who were sick with a particular type of disease could spread the disease from one person to another. He knew there was a factor involved in the spreading of diseases.
Ibn Sina wrote all his observations and findings in books which are of great importance even today.
